Scientific evidence to support estimates of risk of cancer deaths from diesel exhaust "is lacking at this time" but this judgment doesn't close the question of possible effects of diesel emissions on human health, the Diesel Impacts Study Committee of the National Research Council Assembly of Engineering advised the U.S. Environmental Protection Agency. The committee's opinion was delivered in a critique--requested by the agency--of the Environmental Protection Agency Carcinogen Assessment Group's June 11, 1979, report, Initial Review on Potential Carcinogenic Impact of Diesel Engine Exhaust. The critique, untitled, went to the agency in December. The critique notes that because effects of diesel exhaust on humans haven't been studied directly the Initial Review uses risk assessments analogous to those for other exposures to hydrocarbon combustion products; such assumptions are questionable, the critique declares. The Initial Review reported "highly consistent carcinogenic potency...in different epidemiological studies for the following varied hydrocarbon combustion product exposures, measured as BaP (benzo(a)pyrene): (1) coke oven emissions, (2) roof tar volatiles, (3) gas works emissions, and (4) general air pollutants as measured by BaP in particulates." The Diesel Impacts Study Committee's Panel on the Health Effects of Diesel Emissions cited "limitations of comparisons of coke oven and diesel engine emissions" and "concluded that the assumptions forming the basis of...Initial Review were insufficiently supported by verifiable scientific evidence to permit their application to the effects of deisel engine emissions. The comments by DISC (Diesel Impacts Study Committee) are not meant to imply that adverse health effects may not be associated with the operation of a sufficiently large number of diesel-powered vehicles in urban communities. Indeed, it may turn out that harmful or even dangerous consequences to human health are related directly to diesel emissions, but the scientific evidence to support numerical risk estimates of cancer deaths is lacking at this time. Furthermore, a realistic risk assessment ought not to be directed to cancer only but to overall morbidity and mortality from other causes, particularly from chronic lung disease. In addition, the available evidence on "catastrophic" episodes of air pollution, together with experimental data on common pollutants, should be included in such assessments. Consideration of these factors, as well as the outcome of the ongoing research..., can be reasonably expected to lead to a scientifically credible risk assessment. To do less would leave any risk assessment of diesel automobiles open to challenge." (Author)

  • Corporate Authors:

    National Research Council

    2101 Constitution Avenue, NW
    Washington, DC  United States  20418
  • Publication Date: 1980-2

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  • Accession Number: 00308482
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 22 1980 12:00AM